The day after Iraq's al-Qaida affiliate warned that it was readying for a new offensive, a new offensive came. The co-ordinated attacks – about 30 in total – killed more than 107 people and shattered the government narrative that the terror group has been defeated.

The large toll is the biggest daily casualty figure in more than two years. It follows two other choreographed strikes in the last six weeks that showed the ease with which bombers, assassins and their enablers can plot carnage in Iraq, more than seven months since US forces withdrew.

The attacks were centred near the heartland the group carved for itself during those bloody years – a swath of Iraq north of Baghdad, which an Islamic State of Iraq member said last week the group was trying to reclaim. By mid-afternoon bombings and shootings had spread throughout the centre of the country and to Baghdad itself, both also flashpoint areas in the Sunni-led insurgency that took centre stage during Iraq's sectarian war.

Today's strikes started around dawn with an attack on an army base in Salahedin province, not far from Saddam Hussein's ancestral home of Tikrit in the Sunni centre of Iraq. Attacks have been frequent in Salahedin, which remains a hub of the Sunni establisment that was ousted when Saddam fell and replaced by a succesion of Shia-led governments. They have primarily targeted instruments of the Shia state, particularly security forces.

Bombs targeted army patrols and security officials in Balad, Sadr City and in Baquba province to the north-east of the capital. The attacks were over before noon, seemingly to capitalise on the slow start to the day in Iraq during Ramadan, when many observant Muslims eat before dawn, then sleep during the morning hours.

Viewed in isolation, the attacks are serious enough: the destabilising effect on a country that shows few signs of overcoming deep distrust among its Shias, Sunnis and Kurds is worrying. So too the fact that the postwar hope – the unifying influence of the state – has once again been unable to stop a multi-city slaughter.

However, when seen through the prism of the rest of the region's woes, the latest events take on an even more serious perspective. Neighbouring Syria is fast sliding towards full-blown war, with a real risk of a sectarian spillover into a region that has seen hardening sectarian positions in all corners for the last 18 months.

Like Iraq in 2002, Syria now is a dictatorship cemented by minority rule, with power drawn mostly from one sect that rules over a restive majority.

Unlike Iraq, however, Syria's Sunnis have a lot to gain if the Shia-aligned Alawite sect loses power and influence. Although the Syrian uprising has for the most part mostly been driven by a Sunni population tired of life under the boot of dictatorship, there are growing questions about whether an Islamic extremist element that exists on the sidelines could manoeuvre itself to centre stage.

Al-Qaida's leader, Ayman al-Zawahiri, has made no secret of his view that the Syrian uprising marks an opportunity for the group and its offshoots, who see the Arab spring revolutions as a chance to get one up on the Shias.

The Islamic State of Iraq clearly agrees with him. Intelligence officials in Iraq, Britain and the US believe that some battle-hardened global jihadist fighters have crossed from Iraq into Syria – ironically using the same routes that fellow militants used to use when crossing the other way.

Subversive groups such as al-Qaida thrive in a vacuum. And whether by design or through the inevitable bedlam that the collapse of rigid order brings, a vacuum is fast becoming a major concern in Syria and beyond.

"I will not let this be their moment," a senior Iraqi intelligence official said yesterday. "They will not win here or in Syria. We can't afford to let them get their hands on things again."